1. Field of the Invention
This invention relates to an improvement in space vehicles and more particularly, but not by way of limitation, to a deployable pressurizable bag to fill the aft end of the nozzle of a recoverable rocket booster to preclude entry of salt water into the booster upon landing in a salt water boy for recovery and thereby protect the rocket engine from damage and to eliminate the need for refurbishment of the rocket engine after ocean recovery.
2. Description of the Prior Art
It is well known in the art, to associate a number of solid and liquid rocket boosters and a space vehicle in order to launch a space vehicle or a payload into a desired orbit around the earth or other desired extra-terrestrial path. It is common to use solid rocket boosters and liquid propellant rocket boosters to propel the associated space vehicle to at least a desired first stage of travel. At present, after a launch an attempt is made only to recover, refurbish and reuse solid rocket boosters. The reason for this is that rocket boosters commonly descend into salt water bodies for recovery. Salt water damage to a solid rocket booster is considered to be of minor consequence since the relatively simple rocket motors of such boosters are completely rebuilt prior to reuse. However, in the instance of liquid propellant rocket boosters the crash damage to the rocket body and the subsequent entry of salt water into the thrust chambers and interior of the complex liquid propellant turbopumps render a liquid rocket booster incapable of reuse without having first undergone expensive major overhaul and refurbishment.
Accordingly, it is of paramount importance if an attempt is to be made to reuse a liquid propellant rocket booster to protect the rocket engine from potential impact damage as the liquid rocket booster descends into a salt water body, such as an ocean, and to preclude resulting environmental damage to the engine prior to recovery of the rocket booster from the sea water. Failure to provide adequate protection from these dangers would render a liquid propellant rocket booster uneconomical to use in comparison to a solid rocket booster.
Past attempts at protecting a liquid propellant rocket from such damage have revealed substantial room for improvement. Such efforts have included large mechanically operated closures for the thrust end of the rocket engine. Such a closure was moved from a stowed position outboard of the booster to a deployed position so that the open end of the rocket engine would be sealed in the manner of sealing a jar with a lid.
These devices unfortunately are very heavy, involve complex mechanisms, and cause severe interface problems with the conventional means for securing a rocket booster and associated space vehicle to a launch pad. The problem of adequately protecting a liquid propellant rocket booster for recovery from a salt water body in a practical manner has not been provided by the prior art.
The present invention does provide a simple, low cost, lightweight practical solution to the problem of providing adequate protection for a liquid propellant rocket booster to enable reuse thereof after recovery from a salt water body.
The following patents, while of interest in the general field to which the invention pertains, do not disclose the particular aspects of the present invention that are of significant interest.
U.S. Pat. No. 4,961,550, assigned to the assignee of the present invention, is concerned with the same problem and discloses a rocket booster having a double walled skirt extension in which is disposed a water impermeable flexible sleeve means which extends from the booster after it has landed and is floating in sea water. The sleeve collapses against itself along its length and precludes migration of the sea water into the rocket engine and associated turbopumps. For a more complete description of the rocket booster, the disclosure of U.S. Pat. No. 4,961,550 is incorporated herein by reference.
U.S. Pat. No. 4,504,031 discloses an inflatable braking member that is deployed around a space vehicle by introducing gas into it. The braking member is jettisoned after the space vehicle leaves the atmosphere to enter a low earth orbit.
U.S. Pat. No. 4,638,947 relates to a rocket engine nozzle extension. A pneumatic bag within the fixed nozzle of a rocket engine is inflated to push and unfold the nozzle extension. After the nozzle extension is completely formed, the pneumatic bag may be jettisoned by firing the rocket engine.
U.S. Pat. No. 3,711,027 relates to an extendable nozzle for a rocket engine. The nozzle extension is deployable from a compactly stowed condition to an extended condition. A temporary jettisonable cover member is pressurized to unfurl the extendible nozzle and then is detached.
U.S. Pat. No. 3,482,783 relates to an inflatable rocket nozzle which includes pressure means that expand the inflatable nozzle when the rocket has risen to a predetermined altitude in the earth's atmosphere.
None of the prior art uncovered disclose an arrangement utilizing an inflatable pressurized bladder which acts as a plug to close the nozzle of a liquid rocket booster in a water sealing engagement prior to the landing of the booster in sea water. This arrangement protects a liquid propellant booster rocket from crash damage and environmental damage for recovery of the rocket booster from a sea water landing so as to permit reuse thereof without major overhaul. None of these previous efforts, however, provides the benefits attendant with the present invention.
It is a general object of this invention to provide an improved arrangement for precluding crash damage and sea water damage to a liquid propellant rocket booster when the booster returns to a salt water body for recovery.
It is a further general object of the invention to provide an improved engine protection arrangement for a recoverable rocket booster which is practical, economical to produce and install, and which is lightweight.
It is a specific object of the invention to prove an engine protection arrangement which utilizes a deployable pressurizable bladder which acts as a plug to substantially fill the lower portion of the nozzle of a recoverable rocket booster to preclude entry of salt water into the booster upon landing for a predetermined period of time to permit recovery.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawing.